Starting motor control



Aug. 28, 1962 Filed Aug. 8, 1960 il' ull I R. J. MUEHLHAUSEN STARTING MOTOR CONTROL 2 Sheets-Sheet l Fig. 1.

IN V EN TOR.

RoBERr J. MuEHLHAusEN mm/,zama MMM/M ATTORNEYS Aug. 28, 1962 R. J. MUEHLHAUSEN STARTING MOTOR CONTROL 2 Sheets-Sheet 2 Filed Aug. 8, 1960 INVENTOR. ROBERT J. MUEHLHAUSEN 3,051,136 STARTING MTGR CGNTROL Robert Il. Mnehlhausen, Indianapolis, lud., assignor to Schwitzer Corporation, a corporation of Indiana Filed Aug. 8, 1961i, Ser. No. 47,972 6 Claims. (Cl. 121-37) This invention relates generally to pneumatic starting devices for compression ignition engines and in particular to a pneumatically operated control apparatus for providing a drive connection between the starting motor and the engine flywheel and subsequently actuating the pneumatic starting motor.

When a compression ignition engine is started, its crank shaft must be turned over by some outside means so that the air in the cylinder is compressed at top dead center to such al pressure and resulting temperature that, when fuel is injected, it will ignite and produce a power stroke. here are two important requirements to be fulfilled in the obtaining of satisfactory starting of a compression j ignition engine. These are turning over of the engine at sufcient speed by the outside means or starting motor and the achievement of the correct compression ratio. lf the engine is turned over very slowly, the unavoidable small leaks past the piston rings and possibly through the intake and exhaust valves permit part of the air to escape from the cylinder during the compression stroke. This may lower the compression pressure and temperature at the end of the stroke below those necessary to ignite the injected fuel. lf the compression ratio is not suiciently high, the 4ilnal temperature of the compressed-air charge will be too low for ignition. A new engine has the correct compression ratio, however, among other things the wear of bearings may lower the piston position somewhat and adversely effect the compression ratio. A proper means for starting a compression ignition engine is thus an important factor in the service operation of a compression ignition engine.

Compression ignition engines are conventionally started by various means such as an auxiliary electric motor, an auxiliary gasoline engine, and pneumatically, that is, by a compressed air motor. The present invention is concerned with this latter starting method. The structure of the present invention includes a piston operated by control air pressure to mesh the starting motor pinion gear into the engine flywheel ring gear prior to the application of cranking torque to the gear. The arrangement whereby the drive pinion and flywheel ring gear are engaged prior to the application of cranking torque provides a substantial reduction in acceleration shock loads on the starting mechanism. This sequential engagement of the drive pinion and ring gear and the actuation of the pneumatic starting motor is accomplished by a Valving arrangement which is built into the pinion engagement assembly without requiring any external linkage or valves.

The primary object of the present invention therefore is to provide a control apparatus for engaging and subsequently actuating a pneumatic starting motor for a compression ignition engine.

A further object of the present invention is to provide a control apparatus of the type referred to above in which the movement of a single pressure responsive member is utilized to engage the starting motor pinion gear with the engine flywheel ring gear and also to actuate a control valve for supplying air under pressure to the starting motor.

' A further object of the present invention is to provide a control apparatus which accomplishes the functions referred to above without the use of external linkage or valves.

A further object of the present invention is to provide a simple compression ignition engine starting system utilizite tts att VQune ing the control apparatus referred to above and permitting use of a conventional starting motor and the use of conventional starting technique by the engine operator.

A further object of the present invention is to provide a control apparatus of the type referred to wherein the components of the apparatus are housed within the space occupied by a conventional starting motor clutch housing.

The full nature of the invention will be understood from the accompanying drawings and the following description and the claims.

FlG. 1 is a side sectional view of the control apparatus and the drive engagement assembly.

FlG. 2 is a side sectional view of a conventional air motor coupled to the assembly shown in FIG. l.

FiG. 3 is a schematic View of the pneumatic system in which the apparatus of FIGS. l and 2 is incorporated.

Referring initially to FIG. 1, there is shown a pinion clutch in the engaging assembly indicated generally at 1li and a piston-valve assembly indicated generally at 11. These assemblies are enclosed in a housing 12, through which axially extends a drive shaft 13. The left hand end of the housing, as viewed in FIG. 1, is attached to a gear case 14 and a gear case cover 16 by means of cap screws 17. One face of the cover 16 is flanged outwardly to support a Vconventional ball bearing assembly 13, the ball bearing assembly serving to journal one end of the shaft 13. The opposite end of the shaft is supported within a bearing 19 carried by an extending portion 21 of the housing 12. An oil wick 22 serves to lubricate the bearing. 'Ihe anged end of the housing 12 and the oppositely disposed face of the cover 16 are undercut to provide a recess accommodating a housing end member 23 having a central aperture bordered by an inwardly extending circular sleeve or ilange portion 24.

Encircling the flange portion 24 is a tubular piston 26 which is axially slidable with relation to thev member 23, the piston ring 27 providing a seal therebetween. The piston further carries an external piston ring 2S cooperating with the adjacent housing surface. The peripheral portion of the left hand end is cut away somewhat as is the adjacent portion of the housing 12, to provide an annular chamber 28. The chamber is connected by means of a passage 29 to the air inlet aperture 31.

The right hand end of the piston 26 is of reduced outside diameter and has mounted thereon two shift pins 32 disposed 180 apart, the mounting being accomplished by means of flat headed rivets 33. A piston cap 34 completes the assembly. The pins 32 extend Within the peripheral channel formed in a drive collar member 36 which is rotationally free but fixed axially on an internally splined sleeve 37, a snap ring 3S serving to retain the member 36 on lthe sleeve. The internal splines on the sleeve -37 mesh with the corresponding splines 39 on the shaft 13. The Iright hand end of the sleeve 37 extends into the central bore of a tubular member 41 with an annular abutment 42, cooperating with an adjacent internal shoulder on the member 41, serving to limit withdrawal of the sleeve 37 from the member 41.

As is conventional in drive engagement assemblies the outer surface of the sleeve 37 and the adjacent inner bore surface of the member 41 are spirally splined so that in the event of relative axial movement between the sleeve 37 and the member 41 the member 41 will be rotated slightly for the purpose of insuring engagement of the pinion gear and engine flywheel ring gear to be subsequently described. The outer surface of the member 41 carries an annular boss 43 which is received in a corresponding annular groove in a tubular member 44. The member 44 is keyed at 46 to the hub portion 47 of a pinion gear 48, the gear 4S carrying a bushing 49 and slidable axially along the shaft 13. Adjacent the gear 48 and engaged thereby when the gear is in its extreme right- Ward position, indicated by a broken line 51, is a flywheel ring gear 52, shown only fragmentarily in FIG. 1.

Supported on the shaft 13 is a flanged sleeve 53 carrying an annular face gear 54. The teeth 55 of the gear V54 engage With face teeth S0 formed at the adjacent end of the hub 47. At its opposite side the face gear 54 carries tangs 56 which engage corresponding tangs 57 extending from member 41. A compression spring 58 extends between the anged end of the sleeve 53 and the opposed portion of the gear 54. The teeth 50 and 55 are of the ratchet or over-running type and provide a conventional over-running clutch for disengagement of the drive shaft 13 from the pinion gear 4S in the event that the engine starts While the pinion gear is engaged with the ring gear 52. During such over-running operation, the gear 54 moves leftwardly as viewed in FIG. 1 compressing spring 8.

A seal cup 59 and seal Washer 61 serve to permit axial movement of the member 44 with relation to the housing 12 but provide a dust sealfor excluding dust and dirt from the cylinder bore. A relatively heavy compression spring 62 extends between an annular internal shoulder 63 of the housing and the piston cap 34, thereby urging the piston 26 into its furthermost left hand position as shown in FIG. 1. A somewhat lighter compression spring 64 extends between the end of the member 44 and the collar 36 and resists relative axial movement of the sleeve 37 and the member 41.

A passage orV chamber 66 in the housing 12 communicates with an axial passage 67 formed in the housing, the passage 67 communicating with the outlet aperture 68.

Referring now to FIG. 2, it may be seen that the gear case 1,4 supports by means of a needle bearing assembly 69 the left hand end of the shaft 13. Mounted on the shaft '13 is a gear 71 and a thrust Washer 72. It will be understood that the gear 71 is keyed to the shaft 13 and rotates therewith. Meshing with the gear 71 is a drive gear 73 which is rotated by the shaft 74 of a conventional air motor 76. The air motor includes end plates 77 and 73 and a housing 79, these being supported on the adjacent end face of the gear case 14. The end plates 77 and 78 carry needle bearing assemblies S1 and 82 journaling the shaft 74. The shaft is rotated by a conventional vaned rotor 83 which receives its rotary motion from the passage of high pressure air from the inlet aperture 84 to the exhaust or outlet aperture 86.

Referring now to FIG. 3, the system in which the pinion engagement and starting motor control apparatus are incorporated will now be described. A reservoir of air under pressure is indicated schematically at 87. A line 88 connects the reservoir -to the inlet side of a normally closed, control pressure operated valve shown schematically at 89. The outlet side of the motor valve 89 is connected to the inlet aperture 84 of the air motor described with reference to `FIG. 2, the exhaust air leaving the motor through the exhaust passage 86. Control air Hows through the line 91 which connects to the inlet side of a push button starting valve indicated schematically at 92. It will -be understood that this valve is located in the operators cab or in a position otherwise convenient for access to the push button 93. As will be evident from FIG. 3, the valve, in deactuated position blocks air ow from the inlet line 91 to the outlet line 94 and vents the outlet line 94 to atmosphere. When actuated, the valve 92 seals the line 94 from atmosphere and passes control air from the line 91 to the line 94. The line 94 is connected to the air inlet aperture 31 of the pinion engagement valve `msembly 11. The outlet aperture 68, previously referred to with reference to FIG. l, communicates with a control air line 96. The line 96 communicates with the interior of the housing 97 of the valve 89 and the pressure thus provided acts against a pressure responsive member 98 serving to move the valve -89 to open position upon the presence of control air pressure in the line 96.

In operation, assuming the parts are in their quiescent state and positions shown in FIGS. l and 3, if the push button 93 is actuated control air pressure will be admitted to the line 94. This serves to pressurize the annular chamber 28 (FG. l) and moves the piston 26 rightwardly. This movement of the piston 26 engages the pins 32 with the member 36 and slides the sleeve 37 rightwardly along the shaft 13. This motion of the sleeve 37 is transferred to the member 41 and consequently the pinion gear 48 through the spring 64. In the event that the teeth of the pinion gear 4S are not properly aligned with the teeth of the ring gear 52 as they engage each other, movement of the member 41 will be halted but movement of the sleeve 37 will continue. This rel-ative movement between the sleeve 37 and the member 41 will compress the spring 64 somewhat and, because of the spiral splines between the sleeve 37 and the chamber 41, the pinion gear 43 may be rotated slightly so as to press the pinion teeth into mesh with the ring gear teeth. The consequent relieving of the spring 64 will then move the pinion into driving engagement with the ring gear.

As the piston 26 thus completes its rightward movement, the chamber 66 will be uncovered by the piston permitting communication -between the chamber 66 and the chamber 28. Control air pressure will thus be caused to exist at the outlet aperture 63 and in the line 96 (FIG. 3). The existence of control air pressure in the line 96 causes the valve 39 to open thereby admitting high pressure air to the inlet aperture S4 of the air motor. Actuation of the air motor, through the gears 73 and 71, rotates the shaft 13 and consequently the pinion gear 4S. The `air motor thus turns over or cranks the engine as long as the valve 89 remains open. When the engine starts, the push button 93 may be released permitting control air to be vented from the line 94. This relieves the pressure in the chamber 28 and the spring 62 returns the piston 26 to its position of FIG. 1 disengaging the pinion from the ring gear. Line 96 is also vented to atmosphere through the starting valve 92 causing the motor inlet valve 97 to close stopping the air to the starting motor. At the time the engine starts and before the pinion gear 48 is disengaged, the over-running clutch provided by the teeth 56 and 57 prevents transmission of torque from the engine to the drive shaft 13.

From the foregoing, it will be evident that the structure described provides for positive engagement of the pinion and ring gears prior to supplying air to the pneumatic `starting motor. The movement of a piston is utilized yto engage .the gears `and also to actuate the control valve to the motor. There is no external linkage required for these functions and the entire structure is built into a conventionally sized housing which i-s interchangeable with conventional structures.

While the invention has been disclosed and described in some detail in the `drawings and fore-description, they are to be considered as illustrative and not restrictive in character, as other modifications may readily suggest themselves to persons skilled in this art and within the broad scope of the invention, reference being had to the appended claims.

. Whatis claimed is:

1. In a pneumatic starting apparatus -for an internal combustion engine or the like of the type which includes a pneumatic motor, a shaft dn'ven thereby and a pinion gear movable axially along the shaft for engagement with the engine ywheel gear: a .tubular housing extending coaxially with said shaft, a sleeve disposed within said housing and extending in coaxial spaced relation therewith, an annular piston slidable along the axis of said shaft between said sleeve and housing walls, a drive collar slidable axially along said shaft for moving the pinion gear, means mechanically linking said collar and said piston, resilient means urging said piston and collar in a direction such as to disengage the pinion gear from the engine flywheel gear, said housing having an air inlet passage therein communicating with the space between said housing and sleeve at one end of said piston whereby upon the introduction of control air under pressure into said passage said piston is moved against the force exerted by said resilient means to engage the pinion gear with the engine flywheel gear, and an air loutlet passage formed in said housing and communicating with the space between said housing and sleeve, said outlet passage being positioned so as to be uncovered by said piston as it completes its pinion engaging movement to thereby allow control air to iiow through said outlet passage only when the pinion gear has engaged the engine llywheel.

2. In a pneumatic starting apparatus for an internal combustion engine or the like of the type which includes a pneumatic motor, a shaft driven thereby and a pinion gear movable axially along the shaft for engagement with the engine -ilywheel gear: a tubular housing extending coaxially with said shaft, a sleeve `disposed within said housing and extending in coaxial spaced relation therewith, an annular piston slidable along the axis of said shaft between said sleeve and housing walls, means mechanically linking the pinion gear and said piston for axial movement of the former by the latter, resilient means urging said piston in a direction such as to disengage the pinion gear from the engine ywheel gear, said housing having an air inlet passage therein communicating with the space between said housing and sleeve at one end of said piston whereby upon the introduction of control air under pressure into said passage said piston is moved against the force exerted by said resilient means to engage the pinion gear with the engine flywheel gear, and an air outlet passage formed in said housing and communicating with the space between said housing and sleeve, said outlet passage being positioned so as to be uncovered by said piston as it completes its pinion engaging movement to thereby allow control air to ow through said outlet passage only when the pinion gear has enga ged the engine flywheel gear.

3. In a pneumatic starting apparatus for an internal combustion engine or the like of the type which includes a pneumatic motor, a shaft driven thereby and a pinion gear movable axially along the shaft for engagement with the engine ywheel gear: a tubular housing extending coaxially with said shaft, a sleeve disposed within said housing and extending in coaxial spaced relation therewith, an annular piston slidable along the axis of said shaft between said sleeve and housing walls, means mechanically linking the pinion gear and said piston for axial movement of the former by the latter, said housing having an air inlet passage therein communicating with the space between said housing and sleeve at one end of said piston whereby upon the introduction of control air under pressure into said passage said piston is moved to engage the pinion gear with the engine flywheel gear, and an air outlet passage formed in said housing and communicating with the space between said housing and sleeve, said outlet passage being positioned so as to be uncovered by said piston as it completes its pinion engaging movement to thereby allow control air to iiow through said outlet passage only when the pinion gear has engaged the engine flywheel gear.

4. In a pneumatic starting -apparatus for an internal combustion engine or the like of the type which includes a pneumatic motor, a shaft driven thereby and a pinion gear movable axially along the shaft for engagement with the engine ywheel gear: a tubular housing, -a piston slidable within said housing, a drive collar slidable axially on said shaft for moving the pinion gear, means mechanically linking said collar and said piston, resilient means urging said piston and collar in a direction such as to disengage the pinion gear from the engine iywheel gear, `said housing having an air inlet passage therein communieating with the space at one end of said piston whereby upon the introduction of control air under pressure into said passage said piston is moved against the force exerted by said resilient means to engage the pinion gear with the engine ilywheel gear, and an air outlet passage formed in said housing and communicating with the space accommodating said piston, said outlet passage being positioned so as to be uncovered by said piston as it completes its pinion engaging movement to thereby allow control air to ow through said outlet passage only when the pinion gear has engaged the engine flywheel gear.

5. A system for controlling a pneumatic starting motor for an internal combustion engine or the like comprising a pneumatic starting motor having a pinion gear engageable with ari engine flywheel gear, a source of air under pressure, a combination pressure responsive actuator and control valve, said actuator serving to engage the starting motor pinion gear with the engine ilywheel gear when supplied with control air pressure and said control valve moving to open position only when said actuator is in pinion engaging position, a first control pressure line connecting said combined valve and actuator to said pressure source, a manually operated normally closed valve interposed in said iirst control pressure line, a high pressure air line supplying air to the starting motor from said air source, a pressure responsive valve controlling the ow of in said high pressure air line and having an actuator adapted to open said high pressure line when supplied with control air pressure, and a second control pressure li-ne provid-ing communication between the outlet side of said control valve and said pressure responsive valve actuator whereby upon actuation of said manually operated valve the starting motor pinion gear is first engaged with the engine flywheel gear and said starting motor is subsequently operated.

6. A system for controlling a pneumatic starting motor for an internal combustion engine or the like comprising a pneumatic starting motor having a pinion gear engageable with an engine ywheel gear, `a .source of air under pressure, a combination pressure responsive actuator and control valve, said actuator serving to engage the starting motor pinion gear ywith the engine flywheel gear when supplied with control air pressure and said control valve moving to open position when supplied with control air pressure, a iirst control pressure line connecting said combined valve and actuator to said pressure source, a manually operated normally closed valve interposed in said iirst control pressure line, la high pressure air line supplying air to the starting motor from said air source, a pressure responsive valve controlling the flow of air in said high pressure air line and having an actuator adapted to open said high pressure line when supplied with control aJir pressure, and a second control pressure line providing communication between the outlet side of said control valve and said pressure responsive Valve actuator whereby upon actuation of said manually operated valve the starting motor pinion gear is engaged with the engine flywheel gear and said starting motor is operated.

References Cited in the tile of this patent UNITED STATES PATENTS 2,802,452 Hageman Aug. 13, 1957 2,849,857 Davids Sept. 2, 1958 2,886,947 Jenny May 19, 1959' 2,906,088 Clark Sept. 29, 1959 FOREIGN PATENTS 20,202 Great Britain Aug. 26, 1915 

